Extract sshParams object

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
Renamed testhelpers packages to fakes

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
Added JSON assertions
Updated FakeFileSystem to save filetype on file/dir/symlink creation

Signed-off-by: Nick Wade <nwade@pivotallabs.com>